1. Field
The present specification generally relates to light diffusing optical fibers for use in illumination applications and, more specifically, to light diffusing optical fibers in which a plurality of helical voids are randomly distributed in the core portion of the fiber to increase scattering induced attenuation losses along the length of the fiber. Methods for making such fibers are also disclosed.
2. Technical Background
Bend insensitive optical fibers may be produced by introducing a random air-line ring into a glass portion of the optical fiber which allows the fiber to be bent to a small diameter without significant attenuation of an optical signal passing through the fiber. The air lines (which are actually gas-filled voids) formed in the fiber generally extend parallel to the long axis of the fiber. Such fibers are structurally similar to standard communication fibers.
Random air-line technology has also been utilized to produce light diffusing optical fibers which have a structure different than that of standard telecommunication fibers. Specifically, light diffusing optical fibers are designed such that light propagating through the fiber is scattered radially outwards along the length of the fiber thereby illuminating the fiber. Random air-line technology has been utilized in light diffusing optical fibers to promote the scattering of light. Like standard telecommunication fibers, the air lines formed in light diffusing optical fibers are generally formed such that the air lines extend parallel to the long axis of the fiber.
However, light propagating through such fibers is readily attenuated and, as a result, the intensity of the light emitted from the fiber decreases with the length of the fiber.
Accordingly, a need exists for alternative light diffusing optical fibers.